Indonesian President Joko Widodo shows his ink-stained finger after casting his ballots during elections in Jakarta, Indonesia, April 17, 2019 in this photo taken by Antara Foto. Antara Foto/Akbar Nugroho Gumay/ via REUTERS

Unofficial results from private pollsters based on vote samples from Wednesday's election pointed to a comfortable win for Widodo, with about 55 per cent of the popular vote, giving him a lead of almost 10 percentage points over his rival, former general Prabowo Subianto.

The counts from reputable pollsters have proved to be accurate in previous elections, though the official result will not be announced until May 22.

Widodo told reporters he had received congratulatory calls from 22 state leaders, including Malaysian Prime Minister Mahathir Mohamad and Turkish President Recep Tayyip Erdogan, and he had invited his rival to meet.

Widodo also urged supporters to wait for official results to confirm the win.

"We must wait for the official result. But 12 pollsters have given clear results ... we convey that the Jokowi-Maruf ticket got 54.5 per cent of the vote while Prabowo got 45.5 percent," Widodo told a news conference in south Jakarta.

At a separate news conference just minutes after Widodo declared victory, Prabowo appeared defiant and said his team had evidence of cheating and claimed to have won 62 percent of the popular vote based on internal polling.

"We have declared (victory) because we got evidence of widespread cheating at the village, sub-district and district levels across Indonesia," he said, standing next to his running mate, Sandiaga Uno, who looked more subdued.

Indonesian presidential candidate Prabowo Subianto (centre) and vice presidential candidate Sandiaga Uno (right) gesture as they declare victory in the country's general election, during a press conference in Jakarta on Apr 18, 2019. (Photo: AFP/IZAAK)

In 2014, Prabowo had also claimed victory on election day, before contesting the results at the Constitutional Court, which confirmed Widodo's win.

A spokesman for Prabowo said he would take his complaint to the Constitutional Court if the Election Commission confirmed Widodo's victory.

The commission said earlier on its website Widodo had secured about 50 percent of the vote, based on results from 808 of more than 800,000 polling stations, with Prabowo on about 45 per cent. The English-language Jakarta Post newspaper carried a front-page headline declaring "Five More Years" next to a picture of the president.

Financial markets surged early on Thursday on Widodo's apparent victory, though gains were pared in the afternoon. The rupiah currency ended the day up 0.3 percent from the previous close, and the Jakarta stock index - at one point up 2.4 percent - closed 0.4 percent higher.

Police vowed firm action against any rallies that could disturb security as Prabowo's supporters planned to march in central Jakarta after midday prayers on Friday.

"I appeal to anyone not to mobilise, whether to mobilise people to celebrate victory or mobilise due to dissatisfaction," said national police chief Tito Karnavian, pledging firm action.

At the same news conference, chief security minister Wiranto called for people to avoid "any act of anarchy that breaches the law"./.

VNF/Reuters